Development of an Electrochemical Impedance Spectroscopy Test to Evaluate Sealants

Distinguishing between sealants and providing laboratory prognostic tools is essential for qualifying new sealants. Current testing does not provide adequate discrimination between sealants. This failure to differentiate is delaying qualification of the new sealants. The concern is that using new sealants in service without sufficient characterization could lead to significant increases in corrosion or maintenance to prevent premature corrosion. Thus, there is a need for a laboratory-based prognostic test that can evaluate the performance of both conductive and non-conductive sealants. DACCO SCI and the Macromolecules and Interfaces Institute (MII) of Virginia Tech propose to develop a laboratory test based on electrochemical impedance spectroscopy (EIS), using a series of patented corrosion sensors, supplemented by adhesive strength measurements and examination of sealed, bimetallic surfaces. This approach will give an early indication of sealant performance so that suitable materials can be chosen for aircraft and other applications.